28 June 2006 The LINC-NIRVANA fringe and flexure tracker: cryo-ambient mechanical design
Author Affiliations +
The correction of atmospheric differential piston and instrumental flexure effects is mandatory for interferometric operation of the LBT NIR interferometric imaging camera LINC-NIRVANA. The task of the Fringe and Flexure Tracking System (FFTS) is to detect and correct these effects in a real-time closed loop. Being a Fizeau-Interferometer, the LBT provides a large field of view (FoV). The FFTS can make use of the large FoV and increase the sky coverage of the overall instrument if it is able to acquire the light of a suitable fringe tracking reference star within the FoV. For this purpose, the FFTS detector needs to be moved to the position of the reference star PSF in the curved focal plane and needs to precisely follow its trajectory as the field rotates. Sub-pixel (1 pixel = 18.5 micron) positioning accuracy is required over a travel range of 200mm x 300mm x 70mm. Strong are the constraints imposed by the need of a cryogenic environment for the moving detector. We present a mechanical design, in which the Detector Positioning Unit (DPU) is realized with off-the-shelf micro-positioning stages, which can be kept at ambient temperature. A moving baffle will prevent the intrusion of radiation from the ambient temperature environment into the cryogenic interior of the camera. This baffle consists of two nested disks, which synchronously follow any derotation - or repositioning trajectory of the DPU. The detector, its fanout board and a filter wheel are integrated into a housing that is mounted on top of the DPU and that protects the FFTS detector from stray light. Long and flexible copper bands allow heat transfer from the housing to the LINC-NIRVANA heat exchanger.
© (2006) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Thomas Bertram, Thomas Bertram, Harald Baumeister, Harald Baumeister, Werner Laun, Werner Laun, Christian Straubmeier, Christian Straubmeier, Steffen Rost, Steffen Rost, Yeping Wang, Yeping Wang, Andreas Eckart, Andreas Eckart, "The LINC-NIRVANA fringe and flexure tracker: cryo-ambient mechanical design", Proc. SPIE 6268, Advances in Stellar Interferometry, 62683L (28 June 2006); doi: 10.1117/12.671378; https://doi.org/10.1117/12.671378


HAWK I A new wide field 1 to...
Proceedings of SPIE (September 29 2004)
Multi-Aperture Spectroscopy At Kitt Peak
Proceedings of SPIE (November 15 1982)
AstraLux: the Calar Alto lucky imaging camera
Proceedings of SPIE (July 10 2008)
Design study for the WIYN high-resolution infrared camera
Proceedings of SPIE (September 29 2004)

Back to Top